Shunsuke Yatabe

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Let A ⊆ [ω]ω be a maximal almost disjoint family and assume P is a forcing notion. Say A is P-indestructible if A is still maximal in any P-generic extension. We investigate P-indestructibility for several classical forcing notions P. In particular, we provide a combinatorial characterization of P-indestructibility and, assuming a fragment of MA, we(More)
This paper proposes a test-case design method for black-box testing, called “Feature Oriented Testing (FOT)”. The method is realized by applying Feature Models (FMs) developed in software product line engineering to test-case designs. We develop a graphical language for test-case design called “Feature Trees for Testing (FTT)” based on FMs. To firmly(More)
We prove a set-theoretic version of Hájek, Paris and Shepherdson’s theorem [HPS00] as follows: The set ω of natural numbers must contain a non-standard natural number in any natural Tarskian semantics of Cà L0(ω), the set theory with comprehension principle within à Lukasiewicz’s infinitevalued predicate logic. The key idea of the proof is a generalization(More)
We investigate what happens if PA LTr2, a co-inductive language, formalizes itself. We analyze the truth concept in fuzzy logics by formalizing truth degree theory in the framework of truth theories in fuzzy logics. Hájek-Paris-Shepherdson’s paradox [HPS00] involves that so called truth degrees do not represent the degrees of truthhood (defined by the truth(More)